Field of the Invention
The present invention relates to a semiconductor substrate, and more particularly, to a semiconductor substrate in which a plurality of electrodes are formed on a base material to protrude therefrom, and a method of manufacturing the semiconductor substrate.
Description of Related Art
For the purpose of enhancing the functionality and downsizing of a system, there has been a demand for a semiconductor device having a smaller size and higher performance, and a technique called “silicon wafer direct bonding” of bonding wafers on which a plurality of micro bumps serving as electrodes are formed to each other has been studied. Such silicon wafer direct bonding is used for micro electro-mechanical systems (MEMS) devices or the like.
In the silicon wafer direct bonding, in order to electrically connect silicon wafers via bumps, a load needs to be applied to the wafers and a required load increases with an increase in the number of bumps. For example, when bumps with a diameter of about 10 μm are formed on an entire surface of a wafer, for example, with a diameter of 8 inches (20.32 cm), the number of bumps is several hundreds of millions and a load required for bonding is several tons. Here, when the bumps have uneven heights, the load is first concentrated on the highest bump and the bump may be damaged. Accordingly, in order to accomplish a decrease in bonding load, a method of planarizing the top surfaces of the bumps by grinding, chemical-mechanical polishing (CMP), or the like has been studied, but it is not easy to evenly planarize several hundreds of millions of bumps without damage and there is a problem in delivery time and cost.
In this regard, Japanese Unexamined Patent Application, First Publication No. H09-55398 discloses a problem in which an amount of electrode material deposited in a plating process varies depending on electrode pads having different potentials, and thus the thickness (that is, the height of an electrode) varies depending on the electrode pads. In order to solve this problem, a method of forming short-circuit wiring patterns short-circuiting the electrode pads in dicing lines, forming electrodes by plating, and cutting the short-circuit wiring patterns in a dicing process has been proposed. By employing this configuration, potential differences between the electrode pads decrease due to the short-circuit wiring patterns and it is thus possible to suppress any unevenness in thickness.